| Abstract | In alpine tundra the contribution of subsurface soil horizons to N and C cycling, their intraseasonal variability and
soil/water interaction in the snow-free season have been poorly studied. The hypothesis that subsoil
pedoclimatic factors (soil moisture and soil temperature) and nutrients (extractable N-NH4
+, N-NO3
-, DON,
DOC, Nmicr and Cmicr) can differ significantly from those of the topsoil was tested for 3 snow-free seasons at 3
study sites (site 1, 3 and 5) in the alpine tundra of the NWItalian Alps. In addition, the intraseasonal variability
of both topsoil and subsoil extractable N and C forms was checked monthly from July to October, and they
were related to those measured in the surface water of an alpine lake (Cimalegna Lake). The soil moisture did
not show significant differences between topsoil and subsoil, with the exception of site 5, and was strictly correlated
with the N and C forms studied at both soil depths, except for N-NO3
-. The soil temperature was always
slightly higher in the topsoil than in the subsoil, due to the incident solar irradiance, andwas positively correlated
with topsoil DON and Cmicr. At all study sites, N-NH4
+ and N-NO3
- showed no significant differences between topsoil
and subsoil,while subsoil DON, DOC, Nmicr and Cmicr significantly differed fromthose in the topsoil, especially
at site 5. Only N-NO3
- had a significant intraseasonal variability reaching the highest values in October at both soil
depths, mainly due to the end of the plants growing season. The temporal variation of N-NO3
- concentration observed
in the lake strictly reflects the temporal changes occurred in the soils underling the fundamental role of
soil biocenosis in limiting leaching losses of nitrates. |
| Text | 372984 2017 10.1016/j.catena.2017.03.007 Scopus 2 s2.0 85014945743 ISI Web of Science WOS 000404704000008 Alps Topsoil Subsoil Water Nutrients Contribution of deeper soil horizons to N and C cycling during the snow free season in alpine tundra, NW Italy Magnani A.; Viglietti D.; Balestrini R.; Williams M.W.; Freppaz M. University of Torino, Department of Agricultural, Forest and Food Sciences, Largo Paolo Braccini 2, Grugliasco, TO, , Italy; University of Torino, Research Center on Natural Risk in Mountain and Hilly Environments, NatRisk, , Italy; Water Research Institute IRSA CNR , Brugherio, MB, , Italy; Department of Geography and Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO, 80309 0450, , United States In alpine tundra the contribution of subsurface soil horizons to N and C cycling, their intraseasonal variability and soil/water interaction in the snow free season have been poorly studied. The hypothesis that subsoil pedoclimatic factors soil moisture and soil temperature and nutrients extractable N NH4 , N NO3 , DON, DOC, Nmicr and Cmicr can differ significantly from those of the topsoil was tested for 3 snow free seasons at 3 study sites site 1, 3 and 5 in the alpine tundra of the NWItalian Alps. In addition, the intraseasonal variability of both topsoil and subsoil extractable N and C forms was checked monthly from July to October, and they were related to those measured in the surface water of an alpine lake Cimalegna Lake . The soil moisture did not show significant differences between topsoil and subsoil, with the exception of site 5, and was strictly correlated with the N and C forms studied at both soil depths, except for N NO3 . The soil temperature was always slightly higher in the topsoil than in the subsoil, due to the incident solar irradiance, andwas positively correlated with topsoil DON and Cmicr. At all study sites, N NH4 and N NO3 showed no significant differences between topsoil and subsoil,while subsoil DON, DOC, Nmicr and Cmicr significantly differed fromthose in the topsoil, especially at site 5. Only N NO3 had a significant intraseasonal variability reaching the highest values in October at both soil depths, mainly due to the end of the plants growing season. The temporal variation of N NO3 concentration observed in the lake strictly reflects the temporal changes occurred in the soils underling the fundamental role of soil biocenosis in limiting leaching losses of nitrates. 155 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85014945743 origin=inward Articolo in rivista Elsevier Science 0341 8162 Catena Cremling. Catena Cremling. Catena Cremling. Catena. Cremling. Catena Amsterdam Cremling. Catena Giessen Cremling. raffaella.balestrini BALESTRINI RAFFAELLA |
